The problem isn't PHP, per se, it's people who fall into the trap of seeing how simple it is to create "working" PHP applications, and then think that all this talk about quality and craftsmanship and design patterns is a load of crap.
The same could be said of the damage that old VB6 (and it's cousins VBA and VBScript) did to the software development profession - it created an entire subculture of what I call "Pinocchio Developers", that is developers who think they are real developers but just appear to be developers. When these people get into companies, they tend to foster a culture built around quick fixes and shoddy design, because it's all they know, and tools such as PHP help to foster this with how deceptively easy it is to become a "PHP programmer" without any knowledge of quality, simply by copying and pasting code snippets or writing spaghetti code. Then you get a developer in this company who DOES know about good design, and they become lepers since for years the company has operated on the notion that good design, craftsmanship (e.g. the SOLID principles), and all of these good things aren't really needed because Bob the Programmer built a ball of mud system using PHP, and it works just well enough that it doesn't crash and burn (as someone else said: Broken gets fixed, shoddy lasts forever).
That's why PHP sucks, and that's why PHP is dangerous: It isn't because it's a poor tool, it's because it blurs or even removes completely the line between a good developer and a bad developer.

Look at this incredible thing Ian Baker created. Look at it! What you're seeing is not Photoshopped. This is an actual photo of a real world, honest to God double-clawed hammer. Such a thing exists. Isn't that amazing? And also, perhaps, a little disturbing? That wondrous hammer is a de...